Group VIII noble metal-promoted zeolites, such as platinum-promoted mordenite, are known. They can be used as catalysts in the transalkylation and disproportionation of alkylaromatic hydrocarbons.
It is also known to modify the alumina to silica mole ratio of these zeolites, in particular the hydrogen form of mordenite (referred to as H-mordenite), by treatment with aqueous solutions of fluorine compounds, such as ammonium hexafluorosilicate. The present invention is directed to an improved method of modifying Group VIII noble metal-promoted zeolites.